Durable Tie Downs

The Navy has aircraft tie-downs in their helicopter flight decks aboard Destroyers that should last the expected 40 years life of their ships but are failing prematurely due to severe corrosion and wear; so to meet this need this research and development project will identify new novel metallic superalloys along with a unique innovative design change altering the location of the weld and heat affected zone with the new design having a hardness up to Rockwell C40 and which will meet or exceed requirements and be easily integrated into the current deck design with no changes required to the functional geometry. A turnkey drop-in solution will be identified, designed and laid out utilizing CAE (computer aided engineering) such as CATIA V6  and proof given of its feasibility and performance capability via such advanced stress analysis tools as finite element modeling (FEM) analysis as well as lab accelerated corrosion tests confirming its corrosion resistance. This approach it is felt would result in the optimal solution to satisfy the Navy's need as it will very easily be integrated by following the current maintenance procedure, with little change, for replacing a corroded tie-down with a new one by welding it in place, The only changes are the new tie-down will be one made of a new novel metal superalloy that is impervious to corrosion and which meets all strength requirements and the weld location and heat affected zones will be moved to a noncritical location so the crossbars will be unaffected in strength retaining their full 185 KSI ultimate tensile and 150 KSI yield strengths and yet the functional geometry of the tie downs will remain unchanged. Due to the superalloy being much greater in strength than the old AISI 4130 tie-downs no change in the size, geometry or shape would be necessary of the functional portion of the geometry. This means there is the added advantage that all interfacing tie-down fittings ( hook and chain assembly that attach tie downs to aircraft) can retain their exact size, geometry and shape too - no learning curve would be needed for flight crew personnel because the replacement design would for all intents and purposes seem identical to the users. It is felt such a solution is closest to an optimal one possible. The result will be durable tie downs never needing replacement that have a higher load capacity to the ones they replace. During phase 1 research and development a couple variations of this approach will be considered and finalized with proof of concept being provided by lab tests and CAE and FEM (finite element modeling) engineering work in preparation for building a prototype during phase 2 work and delivering to the Navy for their verification tests. Later in phase 3 we will assist the Navy in integrating these new tie-downs and a product will be commercialized and made available to the general public.